Differential expression of genes in Drosophila koepferae reared in alternative host plants

CORIO C.; RUSSO M.G.; BETTI M.; SOTO E.; FANARA J.J.; HASSON E.

Kansas City

Congreso; 7th Ecological Genomics Symposium; 2009

Drosophilakoepferaeis a cactophilic species that belongs to the D.buzzatiicluster (repleta group). This species uses as breeding sites thenecrotic tissues of the columnar cacti of the genus Trichocereusas primary hosts and prickly pears of the genus Opuntiaas secondary hosts. These cactaceae differ in chemical compositionand in the microflora associated to the decaying tissues. Previousstudies revealed that flies that emerged fron the cardón T.terschekiiand the prikly pear O.sulphureaexhibit phenotypic differences in traits related to fitness. In fact,D.koepferae exhibitsa better performance when larvae develop in cardón. In order todetermine whether these differences can be accounted forresource-specific gene expression paterns, we generated ESTslibraries from third larvae reared in cardón and pickly pear.Subsequently, we used the technique of substractive hycridization toobtein libraries enriched either with genes over-expressed in larveareared in T.terschekii,or with genes over-expressed in larvea reared in O.sulphurea.The resulting products were cloned and sequenced, and the scriptswere compared with the D.melanogastergenome database. We identified 12 genes in larvea reared in T.terschekii,and other 9 genes that were over-expressed in larvea reared in O.sulphurea.The genes identified from both libraries are involved in diversebiological processes such as: ethanol oxidation, regulation of geneexpression, biosynthesis of oligosaccharides, activity of peroxidase,development of the lymphatic gland, epithelial cell polarity, etc.The variety of biological processes involved in the differential useof alternative hosts suggests an important genotype by environmentinteraction that would play an important role in the adaptiveresponse during host shifts, and that the mechanisms that regulategene expression would be target of host selection.